Congratulations! You are on your way to a grey't relationship with T-bird! He will also get closer to you as he observes how you interact with your Congo. What is your Congo's name? How is your Congo reacting to a new flock member?
Yes. There are differences between the two species. The Timnehs tend to be calmer than the Congos. Although there is no definitive scientific research, particularly on the Timneh, we suspect that the Congos and Timnehs are brought up differently in Nature. We think the Timneh may be nurtured more like the South American birds, which means they are prepared to join the flock at fledging. The Congos are what is called "slow-maturing" birds, in that they take longer periods to develop before joining the flock. They can be a bit more insecure, as a result. HOWEVER, it is a matter of how well they are brought up. This is explained more thoroughly in my African grey pet manual, African Grey Parrots: A Complete Pet Owner's Manual. You can get an autographed copy from this site or regular copy from Amazon.
Patience and going at T-Bird's pace are key. Keep up the fabuloous work! And thanks for coming to this site.
Blessings,
Maggie-